This relates generally to wireless electronic devices and, more particularly, to testing of wireless electronic devices.
Wireless electronic devices typically include transceiver circuitry, antenna circuitry, and other radio-frequency circuitry that provide wireless communications capabilities. During testing, wireless electronic devices under test (DUTs) can exhibit different performance levels depending on whether each DUT has been properly manufactured. For example, each wireless DUT in a group of DUTs can exhibit its own frequency response, power efficiency, linearity, dynamic range, downlink sensitivity, etc.
The performance of a wireless DUT can be measured using a radio-frequency (RF) test station. A conventional radio-frequency test station includes a test host, a test unit (i.e., a signal generator), and a test cell. The test unit is wired to the test host. Connected in this way, the test host can configure the signal generator to transmit downlink radio-frequency signals during test operations.
In conventional radio-frequency test arrangements, a wireless DUT is placed into the test cell. The DUT is connected to the test host via a Universal Serial Bus (USB) cable (i.e., the DUT is “tethered” to the test host). A protocol-compliant connection is established between the test unit and the DUT (i.e., radio-frequency signals are conveyed between the test unit and the cellular telephone transceiver of the DUT using a desired radio access technology). The protocol-compliant connection may be formed via a wired path or a wireless path between the test unit and the DUT. Depending on test results gathered using the test unit, a test operator may determine whether the DUT satisfies design criteria.
Testing the radio-frequency performance of a wireless DUT in this way, however, may require the test operator to carefully place each DUT at a predetermined location within the test cell and may require path loss calibration. Because the path loss associated with the wired/wireless path between the test unit and the wireless DUT varies from station to station, reference DUTs sometimes referred to as “golden” reference units may be used to calibrate each station to ensure that test results gathered across the different stations can be compared. Test station path loss calibration performed using golden reference DUTs may be fairly time consuming.
Moreover, protocol-based testing requires more tedious measurement processes and also has a tendency to drop connections between the DUT and test unit when the output power falls below the DUT's downlink sensitivity. Re-establishing the protocol compliant connection in order to complete testing can add significant time and cost to the test process. The presence of the USB cable that is connected to the DUT can also degrade the accuracy of radio-frequency test measurements.
It would therefore be desirable to be able to provide improved ways of testing wireless electronic devices.